For example, I've just found seven observations of Comet 2013 V2 Borisov from January, using the 2m-aperture (!) FTN telescope on Hawaii:http://lcogt.net/observations/search?qu ... mit=Search
By that time the comet had faded down to 16th magnitude, but it's still just discernible on each individual 90-sec exposure, so I've been able to register and stack them in IRIS: